The conduction modification is an effective method to raise the releasing ability of deposited charge in polymers under space environments. The inorganic semi-conductive filler was here chosen to modify the polytetrafluoroethylene. With this particular filler, the volume conduction of the composites varying with the temperature and electrostatic field were measured. The experimental results indicated, with different contents of filler, the temperature-dependent conduction shown a regular variation and the threshold field of nonlinear conduction property under different temperatures declined but nonlinear tendency significantly increased in particular. The modified polymer is considered to limit the level of deep charging to a safe level.